How to use the pn/child_process.execFile function in pn

console.assert(yield fs.exists(oldFile));
		if (!(yield fs.exists(newFile))) { continue; /* Skip this */ }
		/* check for the watermark string; only overwrite if it is present */
		/* this ensures we don't overwrite actually-ported files */
		if (!WATERMARK_RE.test(yield fs.readFile(newFile, 'utf8'))) { continue; }

		/* run our translation tool! */
		var isPeg = /\.pegjs$/.test(oldFile);
		try {
			var args = (isPeg ? [ '--braced' ] : [])
				.concat([
					'--namespace', 'Parsoid',
					'--watermark', WATERMARK,
					oldFile, newFile,
				]);
			yield childProcess.execFile(
				path.join(BASEDIR, 'node_modules', '.bin', 'js2php'), args, {
					cwd: BASEDIR,
					env: process.env,
				}).promise;
		} catch (e1) {
			console.log(`SKIPPING ${oldFile}`);
			continue;
		}
		if (isPeg) { continue; }
		// Now run phpcbf, but it's allowed to return non-zero
		try {
			yield childProcess.execFile(
				path.join(BASEDIR, 'vendor', 'bin', 'phpcbf'), [
					newFile,
				]).promise;
		} catch (e2) { /* of course there were code style issues */ }

stdio: 'inherit',
			}).on('close', function(code) {
				if (code === 0) {
					resolve(code);
				} else {
					reject(code);
				}
			}).on('error', reject);
		});
	};

	var pPARSERTESTS = path.join(__dirname, '..', 'tests', 'parser', targetName);
	var mwPARSERTESTS = path.join(mwpath, file.path);

	// Fetch current Parsoid git hash.
	var result = yield childProcess.execFile(
		'git', ['log', '--max-count=1', '--pretty=format:%H'], {
			cwd: __dirname,
			env: process.env,
		}).promise;
	var phash = strip(result.stdout);

	// A bit of user-friendly logging.
	console.log('Parsoid git HEAD is', phash);
	console.log('>>> cd', mwpath);

	// Create a new mediawiki/core branch, based on the previous sync point.
	yield mwexec('git fetch origin'.split(' '));
	yield mwexec(['git', 'checkout', '-b', branch, oldhash]);

	// Copy our locally-modified parser tests over to mediawiki/core.
	// cp __dirname/tests/parser/parserTests.txt $mwpath/tests/parser

Promise.async(function *() {
	const files = (yield childProcess.execFile(
		'git', ['ls-files'], {
			cwd: path.join(BASEDIR, 'lib'),
			env: process.env,
		}).promise).stdout.split(/\n/g).filter(s => !!s);
	for (let oldFile of files) {
		const newFile = path.join(BASEDIR, 'src', remapName(oldFile));
		oldFile = path.join(BASEDIR, 'lib', oldFile);
		console.assert(yield fs.exists(oldFile));
		if (!(yield fs.exists(newFile))) { continue; /* Skip this */ }
		/* check for the watermark string; only overwrite if it is present */
		/* this ensures we don't overwrite actually-ported files */
		if (!WATERMARK_RE.test(yield fs.readFile(newFile, 'utf8'))) { continue; }

		/* run our translation tool! */
		var isPeg = /\.pegjs$/.test(oldFile);
		try {

// Now run phpcbf, but it's allowed to return non-zero
		try {
			yield childProcess.execFile(
				path.join(BASEDIR, 'vendor', 'bin', 'phpcbf'), [
					newFile,
				]).promise;
		} catch (e2) { /* of course there were code style issues */ }
		// Comment length warnings are bogus...
		yield rewriteFile(
			newFile, /^<\?php\n/,
			'$&// phpcs:disable Generic.Files.LineLength.TooLong\n'
		);
		// So, were we successful?  If not, disable phpcs for this file.
		var codeStyleErrors = false;
		try {
			yield childProcess.execFile(
				path.join(BASEDIR, 'vendor', 'bin', 'phpcs'), [
					newFile,
				]).promise;
		} catch (e3) {
			codeStyleErrors = true;
			yield rewriteFile(
				newFile, /^<\?php\n/,
				'$&// phpcs:ignoreFile\n'
			);
		}
		// Same idea, but for lint errors
		var lintErrors = false;
		try {
			yield childProcess.execFile(
				path.join(BASEDIR, 'vendor', 'bin', 'parallel-lint'), [
					newFile,

return Promise.resolve().then(() => { // catch thrown errors
        const cp = childProcess.execFile(phantomjsCmd, getPhantomJSArgs(options), { maxBuffer: Infinity });

        writeBufferInChunks(cp.stdin, sourceBuffer);

        return cp.promise.then(processResult);
    });
};

var checkout = Promise.async(function *(commit) {
		console.log('Checking out: ' + commit);
		yield childProcess.execFile('git', ['checkout', commit], {
			cwd: path.join(__dirname, '..'),
		}).promise;
		console.log('Restarting PHP');
		yield childProcess.exec(
			'sudo systemctl restart php7.2-fpm.service'
		).promise;
	});
	var titles;

it('should calculate shades 1 through 6 when appropriate', async () => {
      const fillableArgs = [
        '-c', path.resolve('lib', 'test-helpers', 'colors-fillable.js'),
        '-t', path.resolve('lib', 'test-helpers', templateName),
        '-o', testOutputDir,
      ];
      await child_process.execFile(pathToExecutable, fillableArgs).promise;
      const wrapped = await wrap(() => fs.access(testOutputFile));
      expect(wrapped).not.toThrow();
    });

    const wrapped = await wrap(() => child_process.execFile(pathToExecutable).promise);
    expect(wrapped).toThrow();

    const wrapped = await wrap(() => child_process.execFile(pathToExecutable, args).promise);
    expect(wrapped).toThrow();

    const wrapped = await wrap(() => child_process.execFile(pathToExecutable).promise);
    expect(wrapped).toThrow();